Transformer



May '8, 1923. 1,454,638

L. T. GRADY.

TRANSFORMER Filed Jan. 51, 1921 Patented May 8, 1923 UNITED STATES PATENT @FFICE.

LANSON 'l. GRADY, OF VICTOR, COLORADO.

Application filed January 31, 1921.

To all whom it may concern:

Be it known that 1, Lesson T. GRADY, a citizen of the United States, r siding at Victor, coui'ity of Teller, and State of Colorado, have invented certain new and useful improvements in Transformers; and i do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings and to the characters of reference marred thereon, which form a part of this specification.

This invention relates to electrical transformers and more particularly to a combination of transformer and induction coil.

The object of the invention is to provide a means for raising the secondary voltage of a transformer above its normal value. This construction furnishes a means for starting an are between fixed electrodes and for maintaining the are at the normal voltage of the transformer secondary.

In order to more clearly describe my invention, I shall have reference to the accompanying drawing in which Fig. 1 is a plan of the invention in Opera tive form; and

Fig. 2 is a diagrammatic view showing the relation of the parts.

The same reference numerals will be used to designate the same parts throughout the different views.

The magnetic circuit of my transformer consists of a central core 12, about which the primary circuit 1 1 is wound, a second core 15 about which the secondary coil 16 is wound, and two yoke pieces 10 which connect the adjacent ends of the central cores. A third coil 18 is wound about the secondary coil 16. An alternating current is supplied to the primary coil 1 1 by means of conduc tors 20, the circuit being controlled by a switch The secondary coil 16 terminates in conductors 24-, which are connected by means of an interrupter 25 whose armature 125 is positioned adjacent one end of the upper yoke piece 10. The interrupter 25 is conveniently secured by means of a screw 26 and a block of insulation 28 to the upper yoke piece 10. The free end of the interrup ter opposite the armature 125 is provided with a contact a, which co-operates with a fixed contact also indicated at a, to which one of the conductors 24 leads. A condenser C is Serial No. 241,141.

connected across the contacts, and a switch 30 for opening the circuit is provided.

The third coil 18 is connected by means of conductors 32 with a pair of electrodes 3 1 spaced by an air gap, in which an arc is adapted to be established.

In the operation of the device with all circuit-s closed, the alternating current supplied to the primary coil let sets up magnetic lines in the magnetic circuit and induces a current in the secondary coil 16 in the usual manner. The circuit through the terminals of the coil 16 and through the interrupter 25 is of comparatively low resistance, and allows a heavy current to flow in said second ary coil. This sets up magnetic lines in the pole 15 in a direction opposite to the magnetic lines due to the current in the primary coil 1 1. These lines, thus opposing the lines from the core 12, and cause a stray, field from the ends of the yoke 10, which stray field attracts t-he armature 125 of the interrupter 25 and causes separation of the contacts at a. This operation interrupts the current in the secondary coil 16 and allows the stray field in the core 10 to die out. As soon as this stray field las died out, the contacts at (2 again come together and again permit a current to flow in the secondry coil 16. These operations take place in rapid succession and result in rapid vibrations of the interrupter. These rapid vibrations induce a high potential current in the third coil or high voltage seconca'y coil 18, which breaks down the resistance of the air gap between the electrodes 3%: and allows the current which is induced in the coil 18 to flow over the gap and establish an arc. After the arc is started, the switch 30 may be opened, rendering the interrupter 25 inactive. Under these conditions the primary coil 14:, the core 10 and. the third coil 18 become a simple static transformer taking current from the alternating current supply 20. and maintaining the are between the electrodes 84.

-From the foregoing it will be seen that while the coil 16 is a secondary to the coil. 14, it also acts as a primary to the coil 18, and the coil. 18 acts as a secondary to the coil 14, as well as to the coil 16. It will also be seen that the invention provides a transformer in which the windings and circuits are so arranged that the induced current in one secondary winding and its circuits will generate a high potential in the other winding and its circuits, due to the fact that the current in secondary coil 16 is made and broken at great frequency by the rheotome which is connected in its circuit, which results in a high rate of change in the number of lines of force which cut the turns of coil 18. When the current in the first secondary coil 16 is discontinued, the current in the second secondary coil or third coil 18 automatically falls to the voltage which corresponds to the ratio of the turns in the two coils.

I claim:

1. A transformer comprising a closed magnetic path primary coil, a secondary coil, athird coil wound about said secondary coil, all of said coils enclosing said magnetic path, an interrupter connected in circuit with the said secondary coil, means to open said circuit, and spaced electrodes connected in circuit with the third coil between which an arc is adapted to be created.

2. A transformer comprising a closed magnetic circuit having two cores connected by magnetic yokes, a primary coil wound on one core, a secondary coil wound on the other core, a third coil wound about said secondary coil, an interrupter connected in circuit with said secondary coil and positioned adjacent one of said yokes to be attracted by lines of force set up in said yoke by said secondary coil, means to open the circuit of said secondary coil, and spaced electrodes connected with the third coil between which an arc may be created.

3. A transformer comprising a closed magnetic circuit having two cores connected at their ends by magnetic yokes, a primary coil wound on one core, a secondary coil wound on the other core, a third coil wound about said secondary coil, an interrupter connected in circuit with said secondary coil and positioned adjacent one of said yokes to be attracted by lines of force set up in said yoke by said secondary coil, means to open the circuit of said secondary coil, a condenser in said circuit, and spaced electrodes connected with the third coil between which an arc may be created.

1X transformer having a core forming a closed magnetic circuit, a primary winding on a portion of said core, a secondary winding on another portion of said core, said secondary winding having an interrupter in circuit therewith, a switch in series with said interrupter, and a second secondary winding on said core.

5. An alternating current transformer, comprising in combination a core forming a closed magnetic circuit, a primary winding on said core, a secondary winding thereon, means for increasing the voltage in said secondary winding above the normal, said means consisting of a closed coil surrounding said core, and having an interrupter in circuit therewith, and manually operated means for opening the circuit of said coil whereby it becomes inoperative.

In testimony whereof I affix my signature.

ILANSON T. GRADY. 

